In current Internal Combustion Engines (ICE), efforts have been employed in reducing emissions and fuel consumption. One of the alternatives is the reduction of the idling speed of the engines. However, such strategy involves great challenges from the aspect of torsional vibrations in the Front-End Accessory Drive (FEAD) system. Because it is coupled to the largest inertia of the FEAD assembly, the alternator pulley should provide a good vibration attenuation capability. The objective of this work is to demonstrate the development of an automotive component that employs two distinct types of springs: a clutch spring and a torsion spring. These elements are required in alternator pulleys to reduce torsional vibration generated by the crankshaft fluctuation and to avoid damage or durability issue with other components of the FEAD system. Through analytical and numerical models previously developed for each spring applied, the set of springs of the decoupling pulley under development could be properly designed. Through FEA simulation, product performance is confirmed according to the analytical models. Finally, functional prototypes are evaluated in static torque tests and dynamic evaluation in test bench. Simulations in FEA has demonstrated excellent correlation on vibration attenuation levels of the FEAD, by comparison with experimental results.